Texas Instruments 74CBTLV3857DGVRE4

Overview

74CBTLV3857DGVRE4 from Texas Instruments is a 10-bit FET bus switch optimized for 3.3-V SSTL_2 DDR SDRAM data paths, featuring 7–13 Ω on-state resistance, rail-to-rail switching, and integrated 10-kΩ B-port pulldowns. It enables flow-through PCB layout in high-speed memory interfaces with 0.25-ns propagation delay and Ioff partial-power-down support.

For engineers reviewing the 74CBTLV3857DGVRE4 datasheet, 74CBTLV3857DGVRE4 pinout, 74CBTLV3857DGVRE4 application, or 74CBTLV3857DGVRE4 equivalent, key selection criteria include SSTL_2-compatible OE input (VREF ±350 mV), 24-pin TVSOP package thermal performance (θJA = 86°C/W), and guaranteed 100 mA latch-up immunity per JESD 78 Class II.

Technical Context

This device implements a passive FET-based bidirectional switch architecture with no internal logic or level-shifting circuitry. Each of the ten A-B channels operates as an analog pass gate controlled solely by the OE signal, with VREF-derived AC/DC thresholds ensuring compatibility with DDR SDRAM timing margins.

It integrates dedicated biasing structures: a 50-kΩ pullup on OE, 10-kΩ pulldowns on all B-port pins, and supports Ioff isolation during VCC power-down. The absence of internal termination resistors means its on-resistance (7–13 Ω typ.) replaces external series resistors in SSTL_2 source-terminated lines.

Key Specifications

Pinout & Package

74CBTLV3857DGVRE4 uses a 24-pin Thin Very Small Outline Package (TVSOP) with 0.4-mm lead pitch, 4.4-mm width, and 5.0-mm length. Thermal resistance is θJA = 86°C/W, suited for compact DDR memory module layouts with moderate airflow.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 10-bit FET bus switch applications.

Compared with SN74CBTLV3857PWR and SN74CBTLV3857DW, the 74CBTLV3857DGVRE4 delivers optimal board-area efficiency and thermal performance for high-density DDR memory interfaces, while maintaining full functional and timing equivalence across all three packages.

Availability

74CBTLV3857DGVRE4 is available at Aetrix Electronics and suitable for DDR SDRAM memory interfaces, high-speed logic isolation, and test access multiplexing requiring stable component supply, RoHS/Green compliance, and long-term lifecycle continuity.

Supply support for 74CBTLV3857DGVRE4 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company headquartered in Dallas, Texas, delivering analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The 74CBTLV3857DGVRE4 belongs to TI's CBTLV logic family, engineered specifically for high-speed, low-voltage DDR memory interconnects with emphasis on signal integrity, power efficiency, and JEDEC SSTL_2 compliance.

FAQ

What is the function of the VREF pin on the 74CBTLV3857DGVRE4?

The VREF pin on the 74CBTLV3857DGVRE4 sets the reference voltage (0.38 × VCC) used to define the AC and DC switching thresholds for the OE input. It must be externally bypassed with a 0.1-µF capacitor to GND to stabilize the reference and ensure consistent SSTL_2-compatible enable/disable behavior across temperature and voltage variations. This pin is not an output and does not source current.

Does the 74CBTLV3857DGVRE4 support hot-swap or partial-power-down operation?

Yes, the 74CBTLV3857DGVRE4 supports partial-power-down operation via its Ioff feature. When VCC = 0 V, the device isolates the A and B ports to prevent backflow current from live signal lines into unpowered circuitry. This protects downstream DDR SDRAM devices during power sequencing or hot-plug events, and is fully characterized per JESD 78 Class II latch-up standards.

What is the maximum operating frequency supported by the 74CBTLV3857DGVRE4 in DDR applications?

The 74CBTLV3857DGVRE4 is designed for 200 Mbit/s double-data-rate (DDR) SDRAM applications, corresponding to a 100 MHz clock with data valid on both edges. Its 0.25 ns propagation delay and <5 pF OFF-capacitance ensure timing margin compliance in such systems. While not rated for higher DDR generations (e.g., DDR2/3), it remains suitable for legacy DDR-200 and compatible memory interfaces.

Are the 10-kΩ pulldown resistors on the B port of the 74CBTLV3857DGVRE4 internal or external?

The 10-kΩ pulldown resistors on the B port of the 74CBTLV3857DGVRE4 are internal monolithic silicon resistors integrated into the IC die. They connect each B1–B10 pin to GND and remain active regardless of OE state, ensuring a defined low-impedance termination when the switch is disabled - eliminating the need for external pull-downs in DDR SDRAM DQ line designs.

Can the 74CBTLV3857DGVRE4 be used with 2.5-V or 1.8-V systems?

No, the 74CBTLV3857DGVRE4 is specified only for 3.0 V to 3.6 V VCC operation and SSTL_2-compatible OE thresholds derived from VREF = 0.38 × VCC. Using it with 2.5-V or 1.8-V supplies violates recommended operating conditions, degrades on-resistance matching, and risks unreliable OE detection. For lower voltages, TI's CB3T or LVC families offer appropriate alternatives.